Ellagic \El*lag"ic\, a. [F., fr. galle gall (with the letters reversed).] (Chem.) Pertaining to, or derived from, gallnuts or gallic acid; as, ellagic acid. {Ellagic acid} (Chem.), a white crystalline substance, {C14H8O9}, found in bezoar stones, and obtained by the oxidation of gallic acid.